Both affiliates representing the University of Minnesota, UMD and UM-TC, continue to support the research of graduate students in various departments. At UMD, with graduate student Jennifer Adelman, Greg Ojakangas is directing a research project involving computer modeling of the debris environment in low-earth orbit. The goal of the project is to develop a finite-difference model of the evolving orbital debris distribution. In this model, debris orbits are treated as a continuum in an abstract two-dimensional space where the coordinates are apogee and perigee altitude. The figure (right) shows the directions in which debris orbits decay in this space, under the influence of atmospheric drag. When completed, this model will help NASA to understand and quantify the hazards posed by space debris to present and future space missions. Seed support for this project from the MnSGC has helped secure a $21,000 grant from the NASA Johnson Space Center Orbital Debris Program, allowing the project to become the subject of a Master's thesis in UMD's Physics Department.

In the past year, six UM-TC graduate students received MnSGC Research Assistantships. Following is a short description of the areas of study of three of these graduate students:

Mike Jackson, Aerospace Engineering & Mechanics
Mike's thesis study is in the development of a method of analysis of the sensitivities of aircraft trajectories. This method will be applied to the analysis of aircraft trajectory prediction methods in two major areas of the aerospace industry: air traffic control and on-board flight management systems. The application of this method will provide some physical insight into the fundamental drivers and limitations of trajectory prediction accuracy and will help focus the design of the systems on the key drivers of accuracy.

Mike continues to work full-time at Honeywell while nearing completion of his Ph.D.

Gloria Martinez-Arizala , Physics
Gloria's dissertation is concerned with the structure and electrical properties of films which are model systems for quantum phase transitions at low temperatures. Gloria has co-authored two published works in the past year. They are:

Martinez-Arizala, G., A.M. Mack and A.M. Goldman, "Determination of the Role of the Substrate in Ultrathin Metal Films Grown on Amorphous Ge Substrates," Bull. Am. Phys. Soc. 39 (1994).
Nease, B., A.M. Mack, G. Martinez-Arizala, G.C. Spalding and A.M. Goldman, "Amorphous Ge Substrates: Active or Passive Participants in Electrical Transport in Ultrathin Metal Films," Physica B 194-196 (1994).

Gloria will complete her Ph.D. this fall.

Kimberly Marsh , Aerospace Engineering & Mechanics
Kim's research involves the transient spin-up from rest of corotating disk flow using Laser Doppler Velocimetry. The applications of rotating flows range from predicting the weather to the design of rotating machinery.

Kim presented a paper she co-authored at the 4th Annual Iowa Space Grant Conference, held November 3-4, 1994, entitled "The Transcient Spinup of Corotating Disk Flow." She will complete her Ph.D. in the spring of 1996.